Development of Numerical Wind Tunnel Concerned with Wind Engineering

本研究的目的是开发一种能够准确预测建筑物周围湍流流场的数值风洞。数值风洞主要由两部分组成。一个是建筑物周围湍流流场的数值预报系统。另一种是将模拟结果可视化的计算机图形系统。1.建筑物周围空气流动的数值预测建筑物周围空气流动的数值模拟结果受许多因素影响。因此，需要一个诊断系统来检验数值模拟的准确性。利用大涡模拟和k&lt；epsilon&gt；模型等几种湍流模型进行了数值模拟，以评估有限差分格式、边界条件和网格划分对模拟结果的影响。通过将预测结果与作者进行的风洞实验进行比较，验证了这些模拟的准确性。2.计算机图形学的流动可视化系统时间精确的数值方法能够在任何时刻冻结流动，并立即得出建筑物周围整个流场的速度、压力和各种湍流统计数据。应用先进的计算机图形学技术是吸收计算机产生的海量数据的最合理手段。我们使用Apollo域DN550工作站开发了计算机图形系统。该图形系统不仅允许解释数值生成的流场的细节，而且还允许在数值解和实际流动的可视化表示之间进行比较。

The purpose of this study is to develop the numerical wind tunnel which can predict turbulent flowfield around buildings precisely. The numerical wind tunnel consists of main two parts. One is the system for numerical prediction of turbulent flowfield around buildings. The other is the Computer Graphics System to visualize simulated results.1.Numerical prediction of air flow around buildingsResults of numerical simulation of air flow around buildings are supposed to be affected by many factors. So, the diagnostic system is needed for examining the accuracy of numerical simulations. Several types of numerical simulation by means of turbulent models, such as Large Eddy Simulation and the k- <epsilon> model are carried out to estimate the influences on simulated results of finite difference scheme, boundary conditions and mesh dividing system. The accuracy of these simulations is examined by comparing the predicted results with wind tunnel experiments conducted by authors.2.Flow visualization system by means of Computer GraphicsTime-accurate numerical methods have the ability to freeze the flow at any moment in time and to immediately yield velocities,pressures, and various turbulence statistics for the entire flowfield around buildings. The application of advanced computer graphics techniques is the most reasonable means by which to assimilate the massiveamounts of data generated by computers. We developed the Computer Graphics system using the work station Apollo Domain DN550. This graphics system not only allow interpretation of the details of the numerically generated flowfield but also allow comparisons to be made between numerical solutions and visualized representations of actual flow.